Re: WM_GETTEXTLENGTH change in winproc.c

[Alexandre Julliard]

Gerard Patel  writes:
> I don't understand it :
>  case WM_GETTEXTLENGTH:
> 719     case CB_GETLBTEXTLEN:
> 720     case LB_GETTEXTLEN:
> 721         /* there may be one DBCS char for each Unicode char */
> 722         return result * 2;
>
> This has a bad effect on one of my test apps - returns a length of 12
> for a text of 6 characters, displays funny symbols after the text.
>
> The Unicode window proc returns 6, why the unicode/ascii conversion
> should make it 12 ? The Api returns number of chars, not bytes.

The idea is that 6 Unicode chars can yield more than 6 ASCII chars
with DBCS text. The MSDN doc states that WM_GETTEXTLENGTH can return
more than the actual size when mixing ASCII and Unicode.

What does the app do exactly?  Maybe there are cases where the
conversion can be avoided.